1. Field of the Invention
The present invention relates generally to agricultural planters. In particular, the present invention relates to seed tube guards with improved durability for use with agricultural planters.
2. Description of the Prior Art
The first modern planter was the John Deere 7000 series introduced in 1973. It is depicted in FIGS. 1 and 2 of the accompanying drawings. This design utilizes two opener disks 11 that contact at one point 12 and diverge at a small angle to form a furrow 13 in the ground. The depth of the furrow is determined by the adjustable position of the gauge wheels 14. The seed is dropped into a seed tube 15 and falls into the furrow 13. A pair of closing wheels 16 are mounted at an angle behind the seed tube 15 and are spring-loaded to exert a downward force on the ground. The closing wheels 16 close the furrow 13 and thereby cover the seed with soil.
Another component of this system, generally called a “seed tube guard” 21, is shown in FIG. 3. The seed tube guard 21 shown in FIG. 3 is a forging and is basically the same as currently used on John Deere planters. The seed tube guard 21 is made from medium carbon steel and is heat-treated. A seed tube guide 22 was added to keep the seed tube 15 centered on the seed tube guard 21. The seed tube guard 21 is attached to the shank assembly 23 with two ¼ inch diameter roll pins 24 just below the studs 26 to which the opener disks 11 are mounted. The holes 25 in the shank assembly 23 are 5/16 inch diameter and allow the seed tube guard 21 to align itself as the opener disks 11 flex.
Ground pressure causes the opener disks 11 to deflect inward until they contact the wear surfaces 27 of the seed tube guard 21. Although the seed tube guard 21 might deflect rocks and other debris, the seed tube guard 21 mainly protects the seed tube 15 by maintaining a distance between the opener disks 11. A better seed furrow 13 results from maintaining a proper distance between the opener disks 11.
It is generally known that most seed tube guards 21 supplied as original equipment have a short wear life. This is due primarily to the inadequate wear resistance of the material and also the small wear surface 27. The oversize sheet metal holes 25 in the shank assembly 23 are also subject to excessive wear.
Seed tube guards of most other manufacturers are similar to the seed tube guards 21 described above, except they are sometimes made from cast iron. The seed tube guards (not illustrated) on 3000 series planters recently introduced by Kinze Manufacturing are heat-treated steel castings. The mounting of this seed tube guard is substantially different in that it is bolted rigidly to the shank assembly.
International Harvester (IH) and several similar planters (not illustrated) have a guard and a box incorporated into the shank assembly. The apparent purpose of this box is to direct the seed into the furrow without contacting the opener disks. It also would reduce the amount of dry soil dropping into the furrow.
A conventional seed tube guard 21 with a stainless steel box 28 is shown in FIG. 4. The box 28 is welded to the conventional seed tube guard 21, and the seed tube guard 21 is mounted to the shank assembly with 5/16 inch diameter bolts. This arrangement is produced by J.S. Ag Innovations Inc. and is similar to that used on IH planters.
The IH design also incorporates a flexible flap (not illustrated) into the box, the apparent purpose of which is to reduce bouncing of the seed. J.S. Ag Innovations also produces a similar device, but it is mounted into the end of the seed tube.